function s1_goto_dir() {
    cd "si"
}
function s2_touch_empty_file_with_given_name() {
    touch "si"
}
function s3_make_directories() {
    mkdir -p projects/{git,backup}
}
function s4_create_6_files() {
    touch projects/linux{1,2}_{centos,redhat,c_programming}
}
function s5_make_directories_in_git() {
    mkdir -p projects/git/linux{1,2}
}
function s6_move_files_to_dir_1_or_2() {
    mv ./projects/linux1_* ./projects/git/linux1
    mv ./projects/linux2_* ./projects/git/linux2
}
function s7_create_package_and_compress() {
    tar -czvf ./projects/backup/git.tar.gz ./projects/git
}
function s8_delete_dir_git() {
    rm .rf ./projects/git
}
function s9_recover from_git_tar_gz_backup() {
    tar -zxvf ./projects/backup/git.tar.gz ./projects
}
function s10_create_package_and_compress() {
    tar -jcvf ./projects/backup/git.tar.bz2 ./projects/git
}
function s11_find_and_sort_alphabetically_all_files_and_dirs() {
    find ./projects |sort
}
function s12_get_next_15_minutes_boundary() {
   date -d "@$(($(date +%s)-$(date +%s) % 900 + 900))" +"%Y-%m-%d %H:%M:%S"
}

